As the prepaid market competition gets even hotter, Boost Mobile, Sprint's prepaid service provider, introduced today the Monthly Unlimited with Shrinkage. The no-contract wireless service now offers its customers the opportunity to reduce their $50 monthly unlimited plan to a monthly price of $35 by simply making on-time payments. For every six on-time payments, a customer's monthly cost will shrink by $5, eventually getting down to $35 a month for unlimited nationwide talk, text, Web, e-mail, IM and calls to 411. Here is more info:

Shrinkage is available with Boost Mobile Monthly Unlimited and BlackBerry Monthly Unlimited plans. As of Oct. 14, existing Boost Mobile customers simply go to www.boostmobile.com or call 1-888-BOOST-4U to sign up for Shrinkage. New customers coming to Boost on the $50 or the $60 BlackBerry Monthly Unlimited plans as of Oct. 14 will automatically be part of Monthly Unlimited with Shrinkage.

A customer?s on-time monthly payment date is the same day each month and each on-time payment moves the customer?s monthly cost toward the lower amounts. Consumers who miss their monthly payment date will not be penalized; they will not lose any on-time payments accrued toward the next Shrinkage payment milestone or lose any reduced monthly payment already achieved.